Maternity fuels gender pay gap

Published: February 11, 2018 Last modified: February 11, 2018

Gender differences in rates of full-time and part-time paid work after childbirth are an important driver of differences in hourly wages between men and women, a briefing from the respected Institute for Fiscal Studies (IFS) finds.

Wage progression and the gender wage gap: the causal impact of hours of work was commissioned by poverty campaigners the Joseph Rowntree Foundation, and explores the reasons for the gender pay gap of around 20%. It finds that one important factor is that mothers spend less time in paid work, and more time working part-time, than do fathers. As a result, they miss out on earnings growth associated with more experience.

The effect of part-time work in shutting down wage progression is especially striking. Whereas, in general, people in paid work see their pay rise year on year as they gain more experience, the IFS’ research shows that part-time workers miss out on these gains. The vast majority of part-time workers are women, especially mothers of young children.

This accounts for an important part of the gender wage gap. By the time a first child is grown up (aged 20), mothers earn about 30% less per hour, on average, than similarly educated fathers. About a quarter of that wage gap is explained by the higher propensity of the mothers to have been in part-time rather than full-time paid work while that child was growing up, and the consequent lack of wage progression. About a further tenth of that gap is explained by mothers’ higher propensity to have taken time out of the labour market altogether.

The lack of earnings growth in part-time work has a particularly big impact for graduate women. For example, a graduate who has worked full-time for seven years before having a child would, on average, see her hourly wage rise by a further 6% (over and above general wage inflation) as a result of continuing in full-time work for another year, but would see none of that wage progression if she switched to part-time work instead.

Monica Costa Dias, IFS associate director and a co-author of the briefing, said: “There are many likely reasons for persistent gaps in the wages of men and women which research is still investigating, but the fact that working part-time has a long-term depressing effect is an important contributing factor.

“It is remarkable that periods spent in part-time work lead to virtually no wage progression at all. It should be a priority for governments and others to understand the reasons for this. Addressing it would have the potential to narrow the gender wage gap significantly.”